Huge meteorite impact crater found hidden under Greenland ice

The crater is thought to be the result of an iron asteroid of about one kilometre in size

Image The crater is thought to be the result of an iron asteroid of about one kilometre in size

The discovery was made by an global team led by researchers from the University of Copenhagen in Denmark, which said the feature was one of the 25 largest impact craters on Earth.

A 31-kilometre-wide crater under a Greenland ice sheet indicates a kilometre-wide meteorite smashed into the Earth sometime between 12,000 and 3 million years ago, and could have had a "profound" impact on the climate.

Researchers first got a sense of the crater's location in mid-2015 thanks in part to NASA's Operation Ice Bridge, which flew over areas like the Hiawatha Glacier to track changes in polar ice.

Modelling suggested the asteroid was more than a kilometre wide.

It was first discovered in July 2015 when researchers from the Natural History Museum of Denmark, University of Copenhagen, detected a depressed area underneath the glacier while inspecting a new map of its physical features. To put it in perspective, NASA says the crater is bigger than the Capital Beltway in Washington.

A large hunk of an iron meteorite that was found near Hiawatha years ago now sits in the courtyard of the Natural History Museum in Copenhagen and it was researchers there who drew the connection.

Dr Iain McDonald, from Cardiff University's School of Earth and Ocean Sciences, co-authored the research, which has been published in the Science Advances journal.

He said: "While it requires more research, we consider it possible that the Cape York irons may have been outer fragments or even boulders on the surface of the main meteorite. We suspect these initially detached in Earth's gravity field and then decelerated as they entered the atmosphere to fall south of the Hiawatha crater".

"The crater is exceptionally well-preserved and that is surprising because glacier ice is an incredibly efficient erosive agent that would have quickly removed traces of the impact", lead author of the study Kurt Kjaer said.

"The next step in the investigation will be to confidently date the impact. It is therefore very reasonable to ask when and how and this meteorite impact at the Hiawatha Glacier affected the planet".

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